You can access the created custom fields by using the "id" in the mapping. The "id" always has to start with "c_".

Examples:

    {
    "customFields": [
        {
            "type": "INPUT",
            "id": "c_description",
            "label": {
                "DE": "Beschreibung",
                "GB": "Description"
            },
            "properties": {
                "defaultValue": ""
            }
        },
        {
            "type": "SELECT",
            "id": "c_productInterest",
            "label": {
                "DE": "Produktinteresse",
                "GB": "Product interest"
            },
            "properties": {
                "defaultValue": "",
                "options": [
                    {
                        "label": {
                            "DE": "",
                            "GB": ""
                        },
                        "value": ""
                    },
                    {
                        "label": {
                            "DE": "snapADDY DataQuality",
                            "GB": "snapADDY DataQuality"
                        },
                        "value": "snapaddy_dataQuality"
                    },
                              {
                        "label": {
                            "DE": "snapADDY VisitReport",
                            "GB": "snapADDY VisitReport"
                        },
                        "value": "snapaddy_visitreport"
                    }
                ]
            }
        },
        {
            "type": "MULTI_SELECT",
            "id": "c_followup",
            "label": {
                "DE": "Nächste Schritte",
                "GB": "Next Steps"
            },
            "properties": {
                "defaultValue": "",
                "options": [
                    {
                        "label": {
                            "DE": "Angebot zusenden",
                            "GB": "Send offer"
                        },
                        "value": "send_offer"
                    },
                    {
                        "label": {
                            "DE": "Termin vereinbaren",
                            "GB": "Schedule appoinment"
                        },
                        "value": "schedule_appoinment"
                    },
                    {
                        "label": {
                            "DE": "Kundenbesuch",
                            "GB": "Customer visit"
                        },
                        "value": "customer_visit"
                    }
                ]
            }
        },
        {
            "type": "DATE",
            "id": "c_date",
            "label": {
                "DE": "Follow-Up Termin",
                "GB": "Follow-Up Appointment"
            },
            "properties": {
                "defaultValue": ""
            }
        }
    ]
}